Globally there are more than 6 billion mobile phone connections and GSMA estimated that in 2010 90% of the world’s population was covered by mobile networks. Analysts have reported that there were about 3.1 million base stations (or cell sites) installed worldwide at the end of 2007.
Mobile and wireless communications networks use radio signals to provide a range of voice, video and other data services to subscribers. The radio signals are transmitted between the fixed radio transmitters and mobile devices.
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For an interactive resource on the operation of mobile phones and networks click here
Mobile communications systems must establish a network of sites serving areas called cells, giving rise to the terms cellular communications and cellphone. As the mobile phone user moves, the call is passed between neighbouring cells, a process called handover. If there are gaps in the available coverage the call could be dropped.
In order to avoid congestion as the number of users grows the network operator will reconfigure the network and divide large cells into smaller sizes. As the cell size decreases, so also does the transmit power. Larger cells may transmit up to 100 watts but cells designed to provide service in buildings transmit at levels similar to other wireless home network equipment.
The WHO has concluded:
‘Considering the very low exposure levels and research results collected to date, there is no convincing scientific evidence that the weak RF signals from base stations and wireless networks cause adverse health effects.’